SOLUTION: In ∆ABC, C=60 degrees, a=12, and b=5. Find c. Thank You

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Question 42355: In ∆ABC, C=60 degrees, a=12, and b=5. Find c.
Thank You
Answer by psbhowmick(878) About Me  (Show Source):
You can put this solution on YOUR website!
From the cosine rule
c%5E2+=+a%5E2+%2B+b%5E2+-+2%2Aa%2Ab%2AcosC
or c%5E2+=+12%5E2+%2B+5%5E2+-+2%2A12%2A5%2Acos%2860%5Eo%29
or c%5E2+=+144+%2B+25+-+120%2A%281%2F2%29
or c%5E2+=+169+-+60+=+109
or c+=+sqrt%28109%29
or c = 10.44 (approx)